Reconstitution of ORP-mediated lipid exchange coupled to PI4P metabolism.

ABSTRACT: Oxysterol-binding protein-related proteins (ORPs) play key roles in the distribution of lipids in eukaryotic cells by exchanging sterol or phosphatidylserine for PI4P between the endoplasmic reticulum (ER) and other cell regions. However, it is unclear how their exchange capacity is coupled to PI4P metabolism. To address this question quantitatively, we analyze the activity of a representative ORP, Osh4p, in an ER/Golgi interface reconstituted with ER- and Golgi-mimetic membranes functionalized with PI4P phosphatase Sac1p and phosphatidylinositol (PI) 4-kinase, respectively. Using real-time assays, we demonstrate that upon adenosine triphosphate (ATP) addition, Osh4p creates a sterol gradient between these membranes, relying on the spatially distant synthesis and hydrolysis of PI4P, and qu

SUBMITTER: Fuggetta N 

PROVIDER: S-EPMC10927502 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature